In a variable volume or expandable chamber baler, the baling operation can proceed relatively smoothly once the initial start up phase has passed and it is only necessary for the bale core to continue wrapping itself with additional layers of material as such materials are picked up and introduced into the baling chamber. The start up or core forming stage, however, can be troublesome, depending upon crop conditions, including the nature of the crop being baled and its moisture content. In some instances, the fresh crop material may not tumble properly within the empty chamber and may thus fail to form the coiled up core in the desired manner; in other instances, the crop material may plug up the infeed region of the baler and/or become wrapped around rotating parts so completely that the operation must be halted and the troublesome materials cleaned out of the machine.
It has been a common practice for many years to utilize a rotating starter roller within the infeed region of the baler to help give the newly arriving materials an extra measure of rotational driving force, thus encouraging them to tumble and coil up in the desired manner for starting the core. However, the presence of the starter roller within the infeed region presents one additional moving part on which stringy, especially high-moisture materials can become wrapped and plugged.